#include<stdio.h>

double fact(int a)
{
	double b=1;
	for(int i=1; i<=a; i++)
	{
		b*=i;
	}
	return b;
}

int main(int argc, char const *argv[])
{
	int m,n;
	scanf("%d %d",&m,&n);
	double C = fact(n)/fact(m)/fact(n-m);
	printf("%.0f",C);
	
	return 0;
}
